Die for making steam-boiler stay bolts



' June 25, 192 9. A, PITKIN 1,718,377

DIE FOR MAKXNG STEAM BOILER STAY BOLTS Original Filed July 19. 1922 2 Sheets-Sheet 1 I I Z WITNESSES.

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n 1929- A. F. PITKIN 71 ,718,377

DIE FOR MAKING STEAM BOILER STAY BOLTS Original Filed July 19. 1922 2 Sheets-Sheet 2 WITNESSES Patented June 25, 1929.

UNITED STATES PATENT OFFICE.-

ARTHUR F. PITKIN, OF SCHENECTADY, NEW YORK.

DIE FOR MAKING STEAM-BOILER STAY BOLTS.

Original application filed July 19, 1822, Serial No. 576,027. Divided and this application filed February My invention relates to steam boiler stay bolts of the articulated or so-calledfiexible type, and its object is to provide a means and method whereby stay bolts of such type, having a secketed end or ends, may be inexpensively manufactured, of sections sufficiently strong to safely resist the strains imposed upon them in their pressure upon inner and outer sheets of steam boilers.

This application is a division of an application filed July 19, 1922, Serial No. 576,027 which has resulted into Patent No. 1,628,063, May 10, 1927.

The improvement claimed is hereinafter fully set forth.

In the accompanying drawings: Figure 1 is a view, in elevation, of one section of an impressioned die block adapted to the practiee of my invention, with the socket portion of the material operated on shown in section at the conclusion of each operation; Fig. 2, a similar view of a plunger die block, with portions of the plungers shown in section; Figs. 3, 4 and 5, longitudinal central sections through the socket end of the forging, at the conclusions of the first, second, and third op erations, respectively; Fig. 6, a similar section showing the staybolt articulated to a ball member by which it is to be connected to a boiler sheet; and, Fig. 7, a view, in perspective, illustrating the relation of the impressioned and the plunger die blocks.

For the practice of my invention, which is herein exemplified applied in the manufacture of articulated stay bolts having a socket on one end only, although it is equally and similarly applicable in that of stay bolts having a socket on each end, I provide an impres sioned die block which comprises two counterpart sections, A and A, in the meeting faces of which there are formed three impressions or recesses, 11, b, and 0, the rear portions of which, when the counterparts are brought into contact, are of cylindrical section, corresponding to that of the body of the bolt which is to be manufactured. The adjoining portions, a, b and 0, of the impressions, are of greater diameter, and of section corresponding to the periphery of the socket which is to be formed on the bolt, and the extreme front portions, 6 and 0 of the impressions, b and 0, are of cylindrical section and of greater diameter than the portions, 6 and 0'.

To operate in connection With the impression die block, there is also provided a plunger Serial No. 8,140.

die block, B, the face of which carries plungers, cl and cl", of diameters corresponding wlth the portions, a and 6 of the recesses of the impression die blocks, A, and a plunger,

' tiou, which is conducted in a forging machine of any suitable known construction, which does not, in and of itself, form part of my present invention, and is not, therefore, herein set forth, one of the sections, as A, of the impression die block, is moved sufficiently away from the other section, as A, to permit the insertion from the rear, in the impression,

a, of a heated bar stock of material of circular or other suitable transverse section, which is allowed to project from the front of the impression, a, sufiiciently far that when the sections, A and A, are brought together, and the plunger die block, B, is forced forward by the action of the forging machine, the plunger, (Z, of said block, will upset or force inwardly the material of the bar stock, so as to fill the space before it in the portion, a, of the impression, a, the stock being securely clamped between the sections.

The end of the stock on which the plunger, (Z, acts, having been upset to the form shown in the impression, a, in Fig. 1, the bar stock is next inserted in the impression, b, and by the action of the forging machine, is cupped out and brought to the form shown in the portion, b, of said impression, by the plunger, d of the plunger die block, B. In the performance of this operation, there is found to be a small flash or protruding peripheral flange 1, produced on the socketportion, by the metal squeezing out between the die blocks, to remove which the bar stock is placed in the impression, 0, in which the ring, A is inserted, and by another forward movement of the plunger die block, said flash is cut off, thereby completing the formation of the socket.

The stay bolt thus manufactured has a body, 1,- and an integral socket, 1, and is articulatd to the ball, 2, of the plug: member by which its socket end is connected to a boiler sheet, by inserting the ball in the socket, and forcing inwardly, around the ball, the outwardly flaring end of the socket, thereby forming a bearing face on the socket for the ball, and holding the ball in the socket, as shown in Fig. 6. The socket is preferably made of such depth as to present a space, 1, within it between the ball and the socket, which allows a limited range of relative longitudinal move1nent, as set forth in an application for Letters Patent filed by me under date of October 22, 1921, Serial No. 509,551, which has resulted into Patent No. 1,482,085, Oct. 17, 1922. The exterior surface of the socket is also caused to be essentially cylindrical, andconcentric with the axial line of the body, 1, of the stay bolt, thereby provid ing a bearing socket 1", which is of greater thickness at its outer end than on the remainder of its wall, and, by being so thickened, is strengthened to such an extent as to effectually resist any tendency for the bolt to be pulled out of the socket, when in service, by the turning outwardly of the end poraround said edge.

ARTHUR F. PITKIN. 

